This invention relates to telephone apparatus, and more particularly, to a method and apparatus for remotely controlling call forwarding for a given telephone line.
Call forwarding is presently offered as an optional service from the telephone company for telephone users. In using such call forwarding service, one must initiate call forwarding. One system being offered by telephone companies requires the dialing of a call forwarding initiate code "72" onto the telephone line and then waiting for a dial tone to appear in approximately 5 seconds. After this, the call forwarding telephone number is entered onto the line. The telephone system responds with two beeps followed by the ringing of the forwarding number. If the telephone at the call forwarding number is then picked up, the call forwarding function is initiated. If, on the other hand, the call forwarding number is busy or no one picks up, the user must hang up his local phone and repeat the process. The repeating of the process automatically brings the two beep response followed by a dial tone and this time the call forwarding function is automatically initiated.
In order to terminate call forwarding, one must dial the call forwarding terminate code "73" onto the telephone line, wait for two beeps followed by a dial tone. This indicates that the call forwarding function has been automatically terminated.
While call forwarding is useful, at present both initiation and termination of the call forwarding option takes place at a telephone instrument which is connected to the telephone line having the call forwarding telephone service. Accordingly, if the user is at a different location and desires to change the call forwarding number as he moves from place to place, such would not be possible using standard offered equipment.
In order to provide a remotely controlled call forwarding system there is described in U.S. Pat. No. 4,475,009, issued on Oct. 1, 1984, "A Method And Device For Remotely Controlling Telephone Call Forwarding".
In the aforementioned prior art patent, the system provides a call forwarding enable detector which is set and reset based upon the particular state previously entered. Two separate sequences of remote control are provided. If the enable detector indicates that the system has not been set for call forwarding, then the user remotely follows a sequence to set a call forwarding service. The sequence involves the user dialing the number of a given telephone line. The user then inserts a predetermined identification code number. He then inserts the call forwarding telephone number. The system checks the ID number and if it is correct, it will store the forward telephone number and then proceed to dial out a call forwarding initiate code number "72" followed by the number that has just been inserted as the forward telephone number.
If the enable detector has been previously set into a call forwarding mode, then the remote user must follow a separate sequence to terminate call forwarding service. Three levels of security are described in the aforementioned patent. For a security set at zero, the requirement is to enter two telephone calls within a predetermined interval of time. The other securities provide variations on this theme. For example, security of one provides for a temporary termination after each one of the calls as long as there is provided an ID number thereafter within a fixed time. A security of two temporarily terminates after the second call if it is followed by the ID number.
Once the system detects the proper sequence for terminating a call, it will proceed to dial the termination code "73" on the line to terminate call forwarding.
If a remote user wants to change the system from one call forwarding to the other he must first follow the sequence to terminate call forwarding and then independently follow the sequence for setting a new call forwarding.
It is therefore apparent that the remote user must know the previous state of the system. If the user assumes that there is no call forwarding that has been set and therefore proceeds to set a call forwarding signal when in fact the call forwarding detector actually indicates that there was a previous setting, the system will not operate properly. The user will be entering an ID number when the system is actually looking for two calls within a previous fixed period of time. Similarly, if the user believes that a number has been stored, and that the system is in fact in a call forwarding mode, and the user remotely goes to terminate when actually no call forwarding service has been entered, the system is looking for an ID number and the user is redialing within a predetermined interval of time. Therefore, no terminate signal will be sent and no new number will be entered.
Similarly, in order to change from one number to another number, it is necessary for the user to proceed into a first sequence requiring termination of the previous code and then a separate sequence initiating a new call forwarding code. This is quite a time consuming process and also requires the user to remember the complexities of the system.
Other problems with the aforementioned system concerns the possibility of others tampering with the system. If unauthorized individuals are aware that the given telephone line is equipped with call forwarding service, they may attempt to call in and try to insert various ID numbers in an attempt to break the code and thereby redirect all calls to an unauthorized call forwarding number. There is not method in the aforementioned system to detect any such tampering and to advise the user of attempts by unauthorized individuals to invade his system.
Accordingly, while the aforementioned patent provides a proposed system for remotely controlling call forwarding on a given telephone line, the system involves complexities which adversely effect the successful use of such as system.